Air-motor for automatic musical instruments



C. V. JAMESON. AIR MOTOR FOR AUTOMATIC MUSICAL INSTRUMENTS. APPLICATIONFILED MAY 24,1918.

C. V. JAMESON. y AIR MOTOR FOR AUTOMATIC MUSICAL INSTRUMENTS.

APPucATloN HLED MM2-1,1918.

1,395,278-l Patented Nov. 1, 1921,

4-7 2 SHEETS-SHEET 2,

UNITED STATES CHARLESI V. JAMESON,

PATENT OFFICE.

or CHICAGO, ILLINOIS.

l AIR-MOTOR FOR AUTOMATIC MUSICAL INSTRUMENTS.

To all whom t may concern:

Be it known that I, CHARLES V. JAMESON, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented new and useful' Improvements in Air-Motors for AutomaticMusical Instruments, of which the following is a specification.

This invention relates to the air motors employed for driving the musicand take-up rolls of automatic musical instruments, such for instance asplayer-pianos.

Such motors are commonly provided with zgovernors for maintaining auniform air tension therein, regardless of variations of tensionproduced by the main exhaust bellows, and also with a so-called tempobox containing tempo and rewind valves, the former for regulating thespeed of the motor and the music sheet to suit the tempo of the musicand the latter for admitting high orI ungoverned air tension to themotor pneumatics to rapidly re-roll the sheet.

Heretofore these several parts have been manufactured as separateelements, requiring considerable time to install them andcorrespondingly increasing the cost ofthe instrument.

One of the objects of my invention is to combine the several elements ofthe air motor, including the governor and the tempoboX, in a single andcompact Structure, which can be readily installed as a complete unit andplaced in a relatively small space.

Further objects are to improve the construction of the motor with a viewof facili tating access to Ithe regulating means of the governor-spring,and to improve the motor in other respects.

In the accompanying drawings:

Figure 1 is a front elevation of the motor and parts associatedtherewith. Fig. 2 is a transverse vertical section on line 2 2, Fig. 1.'Fig. 3 is a horizontal section of the governor pneumatic on line 3-3,Fig. 2. Fig. 4 is an enlarged horizontal section on line 4 4, Fig. 3. v

Similar characters' of reference indicate corresponding parts throughoutthe several views. Y

1 and 2 indicate the music and take-up rolls of an automatic musicalinstrument, which rolls are driven from the usual horizontal crank shaft3 of the improved air Specication f Letters Patent.

Patented N ov. 1, 1921.

191s. serial No. 236,425.

motor by the usual sprocket gearing shown in the drawings, or any othersuitable'transmission mechanism. This crank shaft is supported bybrackets 4 carried by a substantially upright-valve board 5 secured to aboard 6 or equivalent support. In the preferred construction shown, theboard 6 is rigidly mounted upon a horizontal base or channel-board 7.

8 indicates the customary motor pneumatics or bellows mounted verticallyon the rear side of the board 6 and having their movable membersconnected with the cranks of the shaft 3 by the usual pitmen orconnecting rods 9, this shaft being constantly rotated by the successivecollapse of the series of motor pneumatics in a well known manner. Thevalve mechanism for controlling the action of these pneumatics may be ofany suitable construction. That shown in the drawings comprises slidingvalves 10 moving vertically in guides 11 secured to the face of thevalve-board 5, and connected with the rods 9 respectively by links 12.In the preferred construction shown in the drawings, each link 12 isprovided at its lower end with an adjustable head 13' seated in a notch14 in the upper edge of the valve and pivoted thereinl by a transversepin 15 passing through these parts. The link 12 and the head 13 may beconnected by a screw thread, as shown, so that upon detaching the headfrom the valve, the head can be screwed up or down on the link toproperly regulate the position of the valve with reference to the usualexhaust port 16 and flushing port 17 with which it coperates. This formsa neat and convenient connection between the valve and the link.

As best shown in' Figs. 2 and 4, the flushing port 17 'of each motorpneumatic opens. into the outer atmosphere at the face of the valveboard 5, while the exhaust port 16 communicates with a. suction channel18 formed horizontally in the valve board and extending from end to endthereof. Each' slide valve is provided on its inner side with the usualrecess 19 of the proper length to bridge or connect the companion ports16 and 17 when the valve is lowered, so as to exhaust the correspondingmotor pneumatic 8, while when said valve is raised to the kpomainexhaust bellows.

port 17, causing the inflation of said pneumatic in a well known manner.

The suction channel 18 is connected by a tube or conduit 20 with thesuction or valve chamber 21 of a tempo box 22, preferably arranged onthe front side of the channel board 7 and suitably secured thereto.Arranged in the lower or base portion of the tempo box is asuction-recess or chamber 23 connected through a suitable governor 24with a suction-trunk 25 leading to the usual main exhaust bellows, notshown in the drawings. During the operation ofthe instrument the suctionchamber 23 is constantly exhausted. Connecting the valve chamber 21 ofthe tempo-box with the suction chamber 23 is a tapering port 25acontrolled by a sliding or other suitable valve 26 operated by a rod 27extending through the end wall of the tempo-box. The playing speed ofthe air motor may be controlled by opening the tempo valve more or less,in a common manner.

Thegovernor 24 maintains a uniform air tension in the suction chamber23, irrespective of variations of tension produced by the This governorconsists of a bellows or pneumatic preferably arranged horizontally onthe rear side of the channel board 7i and glued or otherwisey securedthereto. Arranged within this governor is a block 28 secured to itsfixed board 29 and provided with a governing port 30 opening at one sideof the block and communicating by a passage 31 with a channel 32 formedlengthwise in the board 7. This channelis closed at one end andcommunicates at its opposite end with a box or chamber 33 to which thesuction trunk 25 is connected. The port 30 is controlled by avertically-swinging valve 34 pivoted at one end to the block 28 andcaused to bear at its free end against the movable'board of the governorpneumatic 24 by a suitable spring 35 which latter tends to open thevalve. A tube or conduit 36 extending across the channel 32 connects thevalve chamber 21 of the tempo box with the interior of the governorpneumatic. The collapse of this pneumatic is resisted by the customarycoiled spring 37 connected with an arm 38 secured to its movable board.i The front end of this spring is adjustably connected to a fixed lug 39by any suitable adjusting means by which its tension may be regulated.In the construction shown, this spring passes through an opening in saidlug and is stretched more or less by a rotary nut 40 engaging itsconvolutions and bearing against the face of said lug.

41 indicates a stop-spring for the movable board of thegovernor-pneumatic arranged `to encounter an adjustable stop or button42 when the resistance of the main spring 37is overcome, so as toprevent complete collapse of said pneumatic and full closure of thegoverning-valve 34. This stop spring preferably consists of a flat steelstrip secured to the movable board of said pneumatic. This constructionrenders the closing action of this pneumatic practically noiseless.

, 43 indicates a rewind port or passage connecting the chamber 21 of thetempo-box directly with the exhaust passage 32 and controlled by asliding rewind valve 44 within said chamber.

In the normal operation of the motor, the

rewind valve 44 is closed, as shown in Fig.V

4, and the tempo valve 26 is opened more or less, to place the motorpneumatics 8 under the control of the reduced or governed air tension inthe chamber 21 of the tempo-box. Under these conditions, assuming thevalve 10 to be lowered, the air current passes from the motor pneumaticthrough the passage 17, valve recess 19, passage 16, channel 18, tube20, suction chamber 21, tempo port 25a, suction chamber 23, tube 36,governing port 30, passage 31, channel 32 and suction box 33 to thesuction trunk 25. l/Vhen the air tension produced by the main suctionbellows rises above the normal, the governor pneumatic 24 partlycollapses and overcomes the normal resistance offered by the spring 37,thereby partly closing the governor valve and reducing the air tensionin the suction chamber'23 accordingly, while when the tension fallsbelow normal, the spring 37 opens the governor pneumatic farther,thereby uncovering the port 3() to a greater extent and restoring' thetension inv said channel to normal.

`When it is desired to rewind the music sheet, the valve 44 is opened,thus placing the chamber' 21 and the motor pneumatics connectedtherewith under the high air tension in the channel 32 and operating thepneumatics more rapidly, in the usual manner.

It is sometimes desirable to sustain a note or chord for a longer periodthan is effected by the cutting of the corresponding music sheetperforations. When there are no imperfections in the,- parts-of thetempo-box, this can be successfully done by fully closing the tempovalve so as to stop the music sheet and continuing to pump theinstrument to sustain the music. Vhen, however, leakage occurs past thetempo valve under these conditions, owing to its being warped orotherwise defective, the motor pneumatics continue to act slowly,causing the sheet to creep or advance more or less and prematurelystopping the note or chord to be sustained. In order to overcome thisobjection, notwithstanding imperfections in the tempo valve or its seat,I provide suitable means for automatically flushing the tempol box whensaid valve is fully closed, preferably consisting of a port or passageleading from the bottom of this box to the outer atmosphere. The innerend of this port is so arranged as to be fully closed by the tempo valvewhen the latter is open to any extent, as shown in the drawing, and tobe uncovered when the valve is fully closed. The tempo boX and the motorpneumatics connected therewith are thus flushed and the music sheet ispromptly stopped, the instant said valve is closed, thereby enabling theperformer to sustain a given note or chord as long as desired.

By arranging the tempo-box 22 on one side of the channel board 7 and thegovernor on the opposite side thereof, preferably the rear side, theseparts and the board 6 carrying the motor pneumatics and theircontrolling valves are all compactly combined in aI unitary structurewhich may be installed or removed as a single unit. This greatlyJfacilitates the installation of the motor and enables the several partsto be placed in. a small space beside the usual tracker-box.

The easy accessibility of the governorspring 37 permits convenientmanipulation of its regulating nut 4t() While playing the instrument.

I claim as my invention:

l. In an air motor of the character described, the combination of abase-board having a suction-chamber, a governor pneumatic connected Withsaid chamber by a port, a governing valve cooperating with said port andcontrolled by the governorpneumatic, a tempo-box having a valve chamberand a suction chamber, said suction chamber being in communication withsaid governor-pneumatic, said valve chamber communicating with thelast-named suction chamber by a tempo-port, and a regulating valvecontrolling said tempo-port, said tempo-bor` and said governor-pneumaticbeing arranged, the one on the front side and the other on the rear sideof said base-board.

2. ln an air motor of the character described, the combination ot' abase-board having a suction-chamber, a governor-pneumatic connected withsaid chamber by a port, a governing valve coperating with said port andcontrolled by the governorpneumatic, a tempo-box having a valve chamberand a suction chamber, said suction-chamber being in communication withsaid governor-pneumatic, said valve chamber communicating with thelast-named suction chamber by a tempo-port and with the channel of saidbase-board by a rewind port, and valves controlling said tempo andrewind ports, respectively', said tempo-box and said governor-pneumaticbeing arranged, the one on the frontside and the other on the rear sideof said base-board.

In an air motor oi' the character described, a governor pneumatic, aresistance spring therefor, an adjustable stop for the movable board andof said pneumatic, and a second spring carried by said movable board andarranged to encounter said stop When the resistance of the first-namedspring is overcome.

4. ln an air motor of the character described, the combination of themotor pneumatics, the tempo box, the tempo-valve, and means for flushingsaid box when the tempovalve is closed.

5. In an air motor' of the character described, the combination of the.motor pneumatics, the tempo-box having a tempo-port and a flushing port,and a valve controlling said tempo-port and arranged to close saidflushing port when the tempo-port is opened and vice versa.

CHARLES V. JAMESON.

